You'll often hear AI models described as "open" or "closed". The difference affects cost, privacy, control and capability.
Closed models
Closed (proprietary) models are accessed through a company's app or API. You can't download them or see how they were trained in detail.
- Pros: often the most capable, easy to use, maintained and improved by the provider.
- Cons: you depend on the provider's pricing, policies and data handling.
Open models
Open-weight models can be downloaded and run on your own computer or servers, and often customised.
- Pros: more control, privacy (data stays on your machine), customisation, no per-use fees.
- Cons: need technical skills and hardware; the largest may be less capable than top closed models.
"Open" isn't always fully open
Some models share weights but not training data or code, and licenses vary. Check the license before commercial use.
Which should you use?
Most people start with closed assistants for convenience. Businesses with strict privacy needs, developers and hobbyists often explore open models, sometimes using both.